HTTP Error Response Codes¶

When QUIC.cloud CDN is serving your site content, you may encounter various HTTP error response codes. Each requires different actions to clear them up.

503 - Service Unavailable¶

A 503 error indicates that QUIC.cloud is having a problem serving your site. Please open a ticket so that we may diagnose the issue.

520 - Origin Server Unavailable¶

A 520 error indicates that the QUIC.cloud PoP was unable to connect to the origin server. Most likely, the issue is a firewall at the origin server which is blocking connections. This is problematic because QUIC.cloud acts as a proxy service for your domain, and requires access for uncached requests.

Try adding QUIC.cloud IPs to your firewall's allowlist (or request that your hosting provider do so). Be aware that these IPs change often, and the firewall must be kept up-to-date.

If you're still experiencing issues, try the following troubleshooting steps.

Check the Origin Server¶

Ensure the origin server is online and responding to requests. You can check this using commands like ping, traceroute, or curl.

• If you get 0% packet loss, it indicates a stable connection with no packet loss.
• If you get more than 0% packet loss, report the packet loss to your hosting provider for further investigation and resolution.

If your server responds to ping, navigate to LSCache Checker to check the HTTP response code. like so:

1. Click the ADVANCED tab
2. Enter the following values:
   • Address: your origin server's IP address
   • Host: your domain name
3. Click the CHECK button to initiate the request
4. Scroll down to the HTTP Header section. If the HTTP response code is anything other than 200 OK or 301 Moved Permanently, contact your hosting provider for further assistance.

Check DNS Configuration¶

Ensure that the correct origin server IP address is configured in your QUIC.cloud Dashboard. Select your domain, and navigate to Settings. Check Server IP on that page.

If you are using QUIC.cloud DNS, you should also check your DNS Zone. Navigate to DNS Zones and click the Manage Zones button next to the correct domain. Verify that the Value of any A records contain the correct origin server IP address.

Contact Your Hosting Provider¶

If you have taken all the steps above and everything is configured correctly, and you still continue to get 520 errors, there may be other hosting-level reasons. For example:

• A hosting-wide firewall
• Origin server overload
• Origin server timeout

Contact your Hosting Provider or System Administrator with the following details:

• Time (including time zone) when the error occurred
• URL that resulted in the 520 error (for example : https://example.com/path/page)

If the issue is on your hosting provider's end, providing this information should help them figure out what, exactly, happened to cause the request to fail.

Contact QUIC.cloud Support¶

If you have taken all of the steps above, and your hosting provider is at a loss to explain the issue, please submit a ticket to QUIC.cloud support.

Please include the following mandatory information:

• Time (including time zone) when the error occurred
• A screenshot of the 520 error page, that includes the node name (for example : SA-BR-CGH-HYBRID-93)
• URL that resulted in the 520 error (for example : https://example.com/path/page)
• Your origin server's IP address

Rarely a node issue on our end can cause a 520 error, and providing this information in your ticket will help us to find any problems more quickly.

521 - Origin Server Timeout¶

A 521 error indicates that the connection between the QUIC.cloud PoP and your origin server timed out. This just means that there was no activity for a lengthy period of time, and the connection is assumed to be dead. Check that your origin server is up and running.

524 - Site Not Found¶

A 524 error appears if a site is pointed to QUIC.cloud in DNS records, but is not registered as a domain on my.QUIC.cloud. If your domain is registered but you are seeing 524 errors, please open a ticket for further assistance.

If you have removed your domain from QUIC.cloud but you see a 524 error when trying to access the site, it's possible that your computer or DNS network devices have cached DNS records that are still pointing to QUIC.cloud. 

To fix this, you can flush the DNS cache for your computer and DNS network devices then retry accessing the site.

Still having a problem? If you added your domain to the CDN using the CNAME method, you may have forgotten to remove the QUIC.cloud-assigned CNAME record for your domain.

Remove any QUIC cloud CNAME records for the domain and replace them with A records pointing to the domain's IP address.